The invention relates to an endoscope, especially to a rectoscope, wherein connected to a tube there is a head, the housing of which can be closed at the end opposite the tube by means of a detachable cover with a window.
When examining an internal organ by means of an endoscope, thus the rectum in the case of a rectoscope, the rectoscope is first introduced into the rectum, the distal opening of the tube being closed by means of an obturator. After the sphincter has been overcome, the obturator is removed by pulling on its handle, which projects out of the open end on the opposite side to the tube. After this, the rectoscope is introduced as far as desired, by sight. Then the examination of the rectum can begin, the rectoscope normally being withdrawn gradually from the rectum as this is observed.
In order to enable an examination to be carried out when the rectum has been emptied (in this condition the internal walls of the rectum lie touching each other), it must be blown up slightly so that the inner walls become visible. For this purpose, the end of the head housing opposite to the tube can be closed with the aid of the cover so that the compressed air introduced into the rectoscope cannot escape. A connecting fixture fitted on the cover or on the housing of the head is used for the supply of compressed air.
It is clear that the proximal end of the head housing has to be opened and closed as quickly and simply as possible. In the rectoscope described above and disclosed in the published German specification AS-PS 1566 179, on both the cover and the head housing there are complementary surfaces in the shape of a truncated cone so that the cover only needs to be inserted in or withdrawn from the head housing. However, this kind of fixing of the cover on the head housing has the disadvantage that the connection between the cover and the head housing can easily become unsealed as the endoscope is manipulated, and may fall out under the increased internal pressure. In addition, production costs for making the complementary truncated cone surfaces are relatively high. These costs become unacceptably high when supplementary apparatus, such as a camera, for instance, is to be attached to the proximal end of the rectoscope. In this case, either an additional adaptor has to be provided or a truncated cone complementary surface has to be provided at the appropriate point on the supplementary apparatus as well. Moreover, the jerky movements when the cover is put on and taken off are painful for the patient.
In another known rectoscope the cover is attached pivotably and permanently to the head of the housing by means of a hinge. Since the cover cannot be taken off it is always a nuisance when it is not actually in use, for example, when the rectoscope is being introduced into the rectum, or when supplementary apparatus is connected, particularly if the connecting fixture for connecting up a blower is attached to it.